Management of Hip Instability in Spinal Muscular Atrophy in the Disease-Modifying Therapy Era: The “Late Autumn” or “Early Spring” of Neuro-Orthopedics?

Neuro-orthopedics is a field comprising knowledge and methods aimed at the diagnosis and treatment of secondary musculoskeletal disorders resulting from primary nervous system pathology. Historically, the greatest step in its development was associated with overcoming the consequences of the polio epidemic, which marked the “early spring” of pediatric orthopedics. However, for progressive neuromuscular diseases like spinal muscular atrophy (SMA), extrapolation of principles developed for poliomyelitis and cerebral palsy did not produce the desired results, leading to a “late autumn” stage, where aggressive surgical intervention was deemed inappropriate, with surgery only recommended as a palliative for intractable pain or care issues. The advent of disease-modifying therapy for SMA opened a new era. Although patients now survive longer, those with SMA type 1 often do not achieve independent standing or walking, predisposing them to hip subluxation and dislocation. Hip joint pathology in neuro-orthopedic diseases remains a significant clinical challenge; however, no unified terminology exists, and neurogenic hip dislocation differs from DDH in being acquired and progressive, requiring dynamic surveillance rather than a one-time assessment. Comparison of current practices across conditions (DDH, CP, myelomeningocele, arthrogryposis, and SMA) reveals heterogeneous diagnostic criteria, screening protocols, and treatment goals. The migration percentage, used in CP, may be an important criterion, but the threshold may differ. Despite a decade of experience with targeted therapy, no significant prospective comparative clinical study has evaluated reconstructive hip surgery outcomes in SMA. Thus, direct application of principles from other conditions is unlikely to resolve the uncertainty. Residual motor function, as in MMC, the migration percentage, contractures, and upper-limb function should be considered. The challenge parallels the “early spring” era, when thousands of polio survivors needed care. We must design fundamentally new frameworks for solving secondary problems after patients have received a chance at life. International, interdisciplinary, integrative research is urgently needed to define diagnosis, screening, prevention, and surgical indications for hip instability in SMA in the DMT era.